Today I came across the two MCA parameters osc_ucx_progress_iterations
and pml_ucx_progress_iterations in Open MPI. My interpretation of the
description is that in a loop such as below, progress in UCX is only
triggered every 100 iterations (assuming opal_progress is only called
once per MPI_Test call):
```
int flag = 0;
MPI_Request req;
<some MPI call initializing the request>
while (!flag) {
do_something_else();
MPI_Test(&req, &flag);
}
```
Is that assumption correct? What is the reason behind this throttling?
In combination with TAMPI, it appears that setting them to 1 yields a
significant speedup. Is it safe to always set them to 1?
Thanks
Joseph
--
Dipl.-Inf. Joseph Schuchart
High Performance Computing Center Stuttgart (HLRS)
Nobelstr. 19
D-70569 Stuttgart
Tel.: +49(0)711-68565890
Fax: +49(0)711-6856832
E-Mail: schuch...@hlrs.de
